Even Ruminants Don’t Like to Eat the Same Thing Over and Over Again

Kathy’s Note: You know the feeling – eating the same thing over and over again just gets old. In fact, I remember when I was living in Kodiak, Alaska I got so tired of eating Halibut every night, that no matter what new way I figured to fix it, some nights I just didn’t want to eat. As it turns out, even ruminants experience this and variety can encourage them to eat more. While Beth describes an experiment with lambs, it works for all creatures. Here you go:

Offering Rations in Different Flavors Improves Lamb Productivity

Can you name the five receptors in the mouth for taste? The first four, sweet, bitter, salty, and sour, are probably easy to recall but the fifth may be a bit more difficult. It’s umami.

Umami?

Recently, scientists identified new taste receptors in the mouth that recognize protein, called umami receptors. Umami means “tasty” in Japanese.

Utah State University researcher Dr. Juan Villalba wanted to know whether eating a ration with a single flavor, or eating rations offered in multiple flavors, would change how much an animal eats, the hormones regulating how much it eats, and what foods the animals liked most.

To find out, he added flavors to the foods he was feeding to lambs. These flavors are made by a Spanish company to encourage livestock to eat new foods and keep them on feed. Flavors stimulate taste receptors in the mouth and have shown promise for use in feedlots.

During the study, lambs received an alfalfa-barley diet flavored with: 1) sweet, 2) bitter or 3) umami flavor, 4) no added flavor or 5) a choice of all four flavors. Not surprisingly, when given a choice, lambs preferred having a diet with all four flavors. The lambs’ favorite flavor was umami, they preferred sweet and plain equally and bitter was their least favorite flavor.

Lambs offered a choice of flavors ate more feed and grew faster than lambs fed a ration with a single flavor. Lambs offered a choice ate similar amounts of plain and umami and less of bitter and sweet, even though the rations contained the same amount of nutrients.

Intake of lambs fed a single ration was more variable during the day than intake of lambs given a choice of flavored rations. Having a choice of all four flavors also changed certain hormones in the blood. The metabolites responsible for regulating how much an animal eats, increasing the amount eaten when an animal hasn’t yet eaten enough, or decreasing what it eats when it’s had enough, were lower in animals that had diets that included all four flavors.

What Does This Mean For You?

Having a variety of foods to choose from helps animals maintain a steady growth rate. Variety also reduces daily fluctuations in intake which could minimize changes in rumen pH and potentially improve the supply of nutrients to the animal. As a grazier, you can help your animals by offering them pastures with a variety of forages.